Kit for solar water heating system

ABSTRACT

Solar water heating systems that are formed as all-in-one kits that include all the components necessary for assembling the solar water heating systems at a chosen site is disclosed. Depending on the desired system, the kit may for example include a solar collector, one or more supplemental storage tanks, pumps, heat exchangers, valves, fittings, piping, timers, insulation, flashings, hose bibs, supports, brackets, fasteners, sealants and/or the like. In fact, the kit may further include all or some of the necessary tools required to assemble the solar water heating system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority benefit of U.S. Provisional PatentApplication Nos. 60/787,448, filed Mar. 29, 2006, and 60/899,698, filedFeb. 5, 2007, both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to improvements of solar waterheating systems. In one aspect, the present invention relates to solarwater heating systems formed as a kit. In another aspect, an improvedtank adapter is described.

2. Description of the Related Art

Solar heater systems are designed to capture heat from the sun and tostore the solar heat until the heat is needed. In solar water heaters,the heat is ultimately transferred to water. Solar water heaters, whichtypically include a collector and storage tank, come in various formsincluding both active and passive systems.

In active systems, the collector is typically a flat plate collector,which includes a rectangle box, tubes that extend through the box and atransparent cover that covers the box. The tubes help capture heat andtransfer the heat to water inside the tubes. A pump is used to circulatewater from a storage tank through the collector and back to the storagetank (typically located in the house). The pump essentially pumps thehot water from the collector into the tank and the colder water out ofthe tank and into the collector. The pump is typically controlled by acontrol system that activates the pump when the temperature in thecollector is higher than the temperature in the storage tank. Thecontrol system may also deactivate the pump when the temperature in thecollector is lower than the temperature in the storage tank. In somecases, the storage tank may double as a hot water heater in order toback up the solar heating, i.e., it can heat the water when thetemperature of the water in the collector is low. One advantage ofactive systems is that they provide better control of the system andtherefore they can be operated more efficiently than other systems.Furthermore, using the control system, active systems can be configuredto protect the collector from freezing in colder climates.

In passive systems, the heated water is moved via natural convection orcity water pressure rather than using pumps. Although passive systemsare generally less efficient than active systems, the passive approachis simple and economical. Compared to active systems, the passive systemdoes not require controls, pumps, sensors or other mechanical componentsand therefore it is less expensive to operate and further it requireslittle or no maintenance over its lifetime. Passive systems come invarious forms including batch and thermosiphon systems.

Batch systems such as breadbox solar water heaters or integratedcollector storage systems are thought of as the simplest of allconventional solar water heaters. In batch systems, the storage tank isbuilt into or integrated with the collector, i.e., a self-containedsystem that serves as a solar collector and a storage tank. Batchsystems typically consist of one or more storage tanks, which aredisposed in an insulated enclosure having a transparent cover on oneside. The side of the storage tanks facing the transparent cover isgenerally colored black to better absorb solar energy. Batch systems usewater pressure from the city source (or well) to move water through thesystem. Each time a hot water tap is opened, heated water from thestorage tank is delivered directly to the point of use or indirectlythrough an auxiliary tank (e.g., hot water heater). One advantage ofbatch systems is that the water does not have to be stored separatelyfrom the collector. Furthermore, due to the large mass storage, batchsystems typically do not encounter freezing problems in colder climates.

Thermosiphon systems, on the other hand, include a flat plate collectorand a separate storage tank. The flat plate collector may be similar tothe flat plate collector used in the active system. However, unlike theactive system, the storage tank is mounted above the collector toprovide natural gravity flow of water, i.e., the heated water risesthrough the collector to the highest point in the system (e.g., top ofstorage tank) and the heavier cold water in the storage tank sinks tothe lowest point in the system (e.g., bottom of collector) therebydisplacing the lighter heated water. Most literature on the subjectdiscusses placing the storage tank at least 18 inches above thecollector in order to prevent reverse thermosiphoning at night when thetemperatures are cooler.

Unfortunately, systems such as these suffer from several drawbacks. Forone, most systems are bulky devices formed from large, awkward and heavyparts and therefore they are difficult to manage and install. This isespecially true on roofs and for do it yourselfers with limited support.In some cases, due to the weight of the system, the roof underneath thesystem must be made more structurally sound. Furthermore, because thesesystems are large and heavy, the costs of shipping these products areexorbitantly high. In fact, in some cases, the cost of shipping may behigher than the cost of the product itself. Another drawback with thesesystems is that they tend not to be aesthetically pleasing.

SUMMARY OF THE INVENTION

In one aspect, the invention relates generally to solar water heatingkits that are packaged in a single box that may be readily shipped usingordinary package carriers (e.g., UPS, Fed Ex, DHL, etc.). Generally, thekit is intended to include components that are necessary to form a solarwater heating system. The components of the kit will vary based on thenature of the solar water heating system that is to be built. In someimplementations, the kit includes at least one flexible solar collectorpanel, an interface module that includes a heat exchanger, and a pipingsystem for coupling the solar panel to the interface module, and forcoupling the interface module to a storage tank that is not part of thekit. The size of the collector panels and the amount of piping that areincluded may be widely varied in accordance with the needs of aparticular design. Typically, the kit would include at least 20 squarefeet of usable collector surface area and at least 40 feet of flexibletubing, although larger collector areas are generally preferred.

In some embodiments, instructions for assembling a solar water heatingsystem are also included in the kit. The shipping box is preferablysized to conform with a relatively low cost shipping standard such asthe OS2 shipping standard.

The components of the kit may be widely varied based on thespecifications of the system being built. For example, in someapplications, the interface module takes the form of a single unit thatincludes a one or two pumps. The kit may include components such as acontrol unit, a tank adapter, multiple flexible collector panels, adrain back tank and/or other suitable components. In someimplementations where flexible piping is readily available to thepurchasers, the flexible piping may be omitted from the kit.

In another aspect of the invention, a tank adapter suitable for couplinga solar water heating system to a storage tank such as a domestic hotwater tank is described. In this embodiment, the tank adapter includesan integrally formed plastic body having at least three connectionpoints and at least who isolated fluid passages. One end of both thefirst and second passages both through a single (first) connection pointthat is adapted to mate with a single tank port. The other ends of thepassages open through different connection points.

In some embodiments, the tank adapter further includes an extension tubethat is fluidly coupled to the first conduit passage and extends beyondthe first connection point so that when the tank adapter is coupled to atank, the inlet of the second conduit passage is substantially at thefirst connection point and the outlet of the first conduit passage maybe positioned within the tank at a location that is physically separatedfrom the inlet of the second conduit passage. The extension tube may beintegrally formed with the plastic body or may be formed from a separatecomponent. By way of example, the tank adapter may be formed via aninjection molding process.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1 is a diagram of a solar water heating system, in accordance withone embodiment of the present invention.

FIG. 2 is a diagram showing a single boxed kit, in accordance with oneembodiment of the present invention.

FIG. 3 is a diagram of a solar water heating system formed from a kit inaccordance with one embodiment of the present invention.

FIG. 4 is a diagram of a solar panel, in accordance with one embodimentof the present invention.

FIGS. 5A and 5B are diagrams showing a coupling arrangement, inaccordance with one embodiment of the present invention.

FIG. 6A is a diagram showing a collector in an extended form and FIG. 6Bis a diagram showing the collector rolled up and ready to be placedinside a box, in accordance with one embodiment of the presentinvention.

FIG. 7 is a diagram of a roof jack, in accordance with one embodiment ofthe present invention.

FIG. 8 is a simplified diagram of a tank adapter, in accordance with oneembodiment of the present invention.

FIGS. 9A-9B are various diagrams illustrating a compact tank adapter, inaccordance with one embodiment of the present invention.

FIGS. 10A-10F are various diagrams illustrating a compact tank adapter,in accordance with one embodiment of the present invention.

FIGS. 11A-11C show various alternate tank adapter arrangements, inaccordance with several alternate embodiments of the invention.

FIG. 12 is a diagram showing a tank adapter coupled to a hot waterheater, in accordance with one embodiment of the invention.

FIG. 13 is a perspective diagram of a drain back tank, in accordancewith one embodiment of the present invention.

FIG. 14 is a diagram of a control module in accordance with oneembodiment of the present invention.

FIG. 15 is a diagram of a packaging arrangement for a solar system kit,in accordance with one embodiment of the present invention.

FIG. 16 is a chart showing a parts list for a solar system kit, inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention pertains to improvements for solar water heating systemssuch as active direct systems, active indirect systems, passive directsystems, passive indirect systems and the like. The improvements areprimarily related to reducing cost, increasing performance, ease ofinstallation, ease of manufacture and ease and cost of shipping.

One aspect of the invention relates to solar water heating systems thatare formed as all-in-one kits that include all the components necessaryfor assembling the solar water heating systems at a chosen site.Depending on the desired system, the kit may for example include a solarcollector, one or more supplemental storage tanks, pumps, heatexchangers, valves, fittings, piping, timers, insulation, flashings,hose bibs, supports, brackets, fasteners, sealants and/or the like. Infact, the kit may further include all or some of the necessary toolsrequired to assemble the solar water heating system.

In most cases, the all-in-one kit uses highly compact or compactablecomponents that are lightweight and that can be easily coupled togetherto form the solar water heating system. As a result, the solar waterheating system can be easily installed by professional installers oralternatively by do-it-yourselfers (DIYers). In addition, the parts canbe optimized for peak solar performance. Furthermore, all the componentsof the system may be configured to fit entirely into a single boxthereby reducing storage space and shipping costs. In fact, the entireboxed all-in-one kit may be configured to conform to standard shippingsizes and weights as for example OS2.

The kit may for example utilize components that can be folded, bended orrolled into a compact form for packaging and that can be rolled orspread out during installation. The kit may also utilize integrallyformed components or single components with multiple functionalitythereby helping decrease the overall size. The kit may also utilizecollapsible components that can be broken down for packaging andassembled together during installation. The kit may also utilizecomponents that can be coupled together, assembled and/or installedwithout tools or with basic household tools so that the installer is notrequired to make a one use tool purchase. The kit may also utilizecomponents that can be coupled together, assembled and/or installedwithout much experience. For example, the system may be designed so thatit can be assembled without using soldered copper joints. The kit mayalso utilize configurable and modular components with standard fittingsso that system can be configured for different uses (e.g., differentuser loads).

Another aspect of the invention relates to solar water heating systemsthat include components formed from plastic materials. Plastic materialsoffer many advantages over materials traditionally used in solar waterheating systems such as copper, glass and the like. Plastic materialsare lightweight, low cost, and easy to manufacture. Furthermore, theycan be formed into almost any shape thereby allowing unique parts to becreated that either provide additional functionality and/or can be madesmaller. In some cases, plastic parts can be made flexible or bendablethus lending themselves to compactness as discussed above as well asallowing the parts to conform to their surroundings. In one embodiment,a majority of the components are formed from plastic. By way of example,and not by way of limitation the solar collector, housings, piping,fittings, valves, flashings, hose bibs, supports, brackets, fasteners,and/or the like may be formed from plastic materials.

To provide some specific examples, the solar collector can be formedentirely or substantially from plastic materials. Additionally oralternatively, the piping can be formed entirely or substantially fromplastic materials (no copper piping is needed). By way of example, PEXtubing or other similar plastic tubing may be used as the conduitbetween the solar collector on the roof and the rest of the systemlocated within the house. Additionally or alternatively, the fittingscan be formed entirely or substantially from plastic materials. Forexample, the fittings that connect the piping to the solar collector aswell as the fittings that couple the piping to storage tanks.

These and other embodiments of the invention are discussed below withreference to FIGS. 1-16. However, those skilled in the art will readilyappreciate that the detailed description given herein with respect tothese figures is for explanatory purposes as the invention extendsbeyond these limited embodiments.

FIG. 1 is a diagram of a solar water heating system 50, in accordancewith one embodiment of the present invention. In most cases, the solarwater heating system 50 is configured to supplement an existing hotwater heater 52 that comprises a storage tank 53 and heater means 54.However, it should be noted that in some cases, the solar water heatingsystem 50 may be a stand-alone system and thus may include its ownstorage tank and possibly a heater means. By way of example, in two tanksystems, the solar water heating system preheats water in a secondarytank before it enters the conventional water heater tank. In one tanksystems, the conventional water heater tank is the only storage tank.Generally speaking, the solar water heating system 50 supplies hot fluidfor the purpose of heating water stored in a storage tank such as thestorage tank 53 of the hot water heater 52. The heated water stored inthe storage tank can be distributed to a point of use as for examplewhen a hot water tap is opened.

The solar water heating system 50 generally includes two majorcomponents: 1) a solar heater 56 configured to capture solar energy, and2) a circulation system 58 configured to move a fluid between the solarcollector and a storage tank (e.g., storage tank 53).

The solar heater 56 generally includes one or more solar collectors 60that capture solar heat from the sun and transfers the solar heat to afluid contained inside the solar collector 60. For example, during thedaytime, the sun heats up the surface of the collectors 60 and the wallspass this heat to the fluid contained inside the collectors 60. In mostcases, the collectors 60 include one or more channels or conduits thatact as passageways for moving the fluid through the collectors 60.Furthermore, the collectors 60 may be formed from a dark color such asblack so as to absorb a greater amount of the sun's energy.

The collector can be widely varied. The type of collector used generallydepends on the desired needs of the system. Examples of solar collectorsinclude flat plate collector, integral collector-storage systems, andevacuated-tube solar collectors. Flat plate collectors typically includean absorber that can be glazed or unglazed. Flat plate collectors mayalso include an enclosure or they may be enclosureless. Integralcollectors also known as ICS or batch systems feature one or more tankscontained within an enclosure which is typically glazed. Evacuated-tubecollectors feature parallel rows of tubes containing an outertransparent tube and an inner absorber tube.

The circulation system 58 generally includes a piping system 62 and aninterface module 64. The piping system 62 provides a physical conduitbetween the solar heater 54 and storage tank(s). The piping system 62may for example include a cold inlet pipe and a hot outlet pipe. Theinterface module 64, on the other hand, provides a means for interfacingthe fluid contained in the collector 60 with the fluid contained in thestorage tank 53. Depending on the system configuration, the interfacemodule can be widely varied. The interface module may enable passive oractive systems. Furthermore, the interface module may enable directcirculation (open loop) or indirect circulation (closed loop).

In passive systems, the interface module includes various valves but nopumps. The heated water is moved via natural convection or city waterpressure rather than using pumps. Passive systems come in various formsincluding batch and thermosiphon. In thermosiphon systems, heated waterrises through the collector to the highest point in the system and theheavier cold water sinks to the lowest point in the system. Often times,an additional storage tank is needed. In conventional thermosiphoningsystems the storage tank is placed above the collector. However,alternative designs may be used as for example those described in U.S.patent Ser. No. 11/097,983, which is herein incorporated by reference.

In active systems, the interface module includes one or more pumps,valves, and controllers that circulate water or other heat transferfluid through the collector(s). The interface module may also includeone or more temperature sensors that interact with the controller. Whendirect circulation is provided in active systems, the pumps circulatewater from a storage tank through the collector and back to the storagetank. The pump pumps the hot water from the collector into the tank andthe cold water out of the tank and into the collector. When indirectcirculation is provided in active systems, the pumps circulate a heattransfer fluid through the collectors and a heat exchanger. A pump mayalso circulate water from the storage tank through the heat exchanger.The heat exchanger transfers the heat from the heat transfer fluid tothe water as it circulates through the heat exchanger. When water isused as the heat transfer fluid on the collector side, the interfacemodule may further include a drain back tank.

In accordance with one embodiment, the solar water heating system isconfigured as an all in one kit. Conventionally, system installers havebeen required to piece together the system from individual parts andparts from different suppliers. This takes time, and may suffer fromintegration and performance problems due to variations from differentsuppliers, and lack of testing for optimal results. The kit overcomesthese drawbacks as the parts are designed for one another, and ifstandard parts are used they are selected for peak performance (e.g.,based on testing).

The all-in-one kit is configured to include at least the solar heaterincluding any parts associated therewith, and the circulation systemincluding any parts associated therewith. By way of example, the solarheater can include a solar collector, but may also include headers,glazings, enclosures, etc. Furthermore, the circulation system caninclude the piping, the various components of the interface module suchas valves, pumps and controller, and any fittings necessary for couplingall the components together. The all in one kit may also optionallyinclude additional parts such as storage tanks, mounting hardware,and/or the like.

To further enhance the kit, the components of the system can be designedto fit into a single box 66 thereby forming a single boxed kit 68 asshown in FIG. 2. In fact, in one embodiment, the boxed up kit 68 isconfigured to conform to specifications governing oversized shippingboxes so as to eliminate freight shipping where costs can beexorbitantly high. Both Fed Ex and UPS classify long or large, butsomewhat lightweight boxes as oversized. Although these oversized boxesare more expensive to ship than standard normal size boxes they are manytimes less expensive than freight shipping since they can be shipped vianormal ground and air delivery. Boxes can be classified as OS1, OS2 orOS3.

At the time of this writing, for UPS, OS1 is a package with a combinedlength and girth that exceeds 84 inches, and a combined length and girththat is equal to or less than 108 inches, and actual weight is less than30 pounds. For each OS1 package, the billable weight is 30 pounds. OS2is a package with a combined length and girth that exceeds 108 inchesand actual weight is less than 70 pounds. For each OS2 package, thebillable weight is 70 pounds. OS3 package is a package with a combinedlength and girth that exceeds 130 inches, and a combined length andgirth equal to or less than 165 inches, and actual weight less than 90pounds. For each OS3 package, the billable weight is 90 pounds.

Also at the time of this writing, for FedEx, OS1 is a package with acombined length and girth that exceeds 84 inches, and a combined lengthand girth that is equal to or less than 108 inches, and actual weight isless than 30 pounds. For each OS1 package, the billable weight is 30pounds. OS2 is a package with a combined length and girth that exceeds108 inches and actual weight is less than 50 pounds. For each OS2package, the billable weight is 50 pounds. OS3 package is a package witha combined length and girth that exceeds 130 inches, and actual weightless than 90 pounds. For each OS3 package, the billable weight is 90pounds.

In order to have the kit conform to at least one of these standards, thevarious components can be configured to be light weight, integrated,compact, collapsible, foldable, rollable and/or the like. The componentsmay even be configured to nest relative to each other to reduce volumeinside the box 66.

In one embodiment, the solar collector 60 may be a flexible solarcollector. The flexible collector is capable of being rolled up therebyreducing its space requirement inside the box. In fact, the collectorarea to package volume can be significantly increased by rolling thecollector up. Furthermore, the collectors 60 may be modular so thatmultiple collectors can be included in the kit. This may be somewhatanalogous to being collapsible. Additionally or alternatively, thepiping 62 may be formed from flexible tubing. Like the solar collector60, the piping 62 can therefore be rolled up thereby reducing its spacerequirement inside the box 66. Additionally or alternatively, in activesystems, the pumps and heat exchanger associated with the interfacemodule 64 can be integrated together into a single compact module thatis contained in a single housing. Additionally or alternatively, inpassive systems, storage tanks situated on the roof with the collectors60 can be collapsible into smaller components. Additionally oralternatively, in active systems, a tank adapter used to expand a singleconnection point into multiple conduits can be integrally formed into asingle compact part thereby significantly decreasing its size and impactwithin the box 66.

To further enhance the kit, the system 50 can be designed for easyhandling and installation. For example, the components may be designedto come in standard shape and sizes with standard threads, fittings orcouplings that can easily be plugged into one another with little effortand possibly no tools. If tools are required, then at least some ofthese tools can be included in the kit. In one example, the variousplumbing connections are made with male stubs, push fittings or similarmechanisms. This allows a user to simply plug the appropriate partstogether to form the entire system.

In accordance with another embodiment, at least some if not a majorityof the components of the kit are formed from plastic materials. Plasticparts are low cost and easy to manufacture. Furthermore, they arelightweight when compared to traditional materials (e.g., glass andmetal). By decreasing the weight, the collector is much easy to handleand assemble on a roof. In addition, the cost of shipping can bedrastically reduced. Moreover, some plastic materials are flexible andbendable and thus the parts may be capable of achieving a more compactform for packaging thereby further reducing the cost of storage andshipping.

In one embodiment, the solar collector 60 is formed entirely orsubstantially from plastic materials. For example, the absorber, glazingand/or enclosures may be formed from plastic materials. In anotherembodiment, the piping 62 is formed entirely or substantially fromplastic materials. For example, the fittings, pipes or tubes, and/orsimilar parts may be formed form plastic materials. In cases whereflashings, and additional storage tanks are included, these parts mayalso be formed from plastic materials. Housings for various elements asfor example pumps and heat exchangers may also be formed from plasticmaterials.

FIG. 3 is a diagram of a solar water heating system kit 100, inaccordance with one embodiment of the present invention. Although solarwater heating systems can be widely varied as indicated above, in thisparticular embodiment, the system is directed at an active indirectsystem. Thus, the solar water heating system kit 100 generally includesa solar heater 102, which can be mounted on a roof, and a circulationsystem 104 including at least piping system 106, heat exchanger 108,pumps 110 and 112 and a controller 114. The system kit 100 mayadditionally include a drain back tank 116 for freeze protection (amongothers) and a tank adapter 118 for interfacing with an existing hotwater heater 120.

The solar heater 102 includes one or more solar collectors 103, each ofwhich includes an absorber 122 and a pair of headers 124. The absorber122 is configured to capture solar heat from the sun and to transfer thesolar heat to the fluid inside the absorber 122. The bottom header 124Ais configured to receive and temporarily hold incoming cold fluid. Thetop header 124B is configured to temporarily hold and help deliveroutgoing hot fluid. If multiple collectors are used they can beconnected simply by fluidly connecting the top headers together and thebottom headers together. By way of example, a simple fitting 126 may beused between each set of headers 124A and 124B. This chain can becontinued until the desired collector area is achieved (collectors—n+1).In one embodiment, the solar collectors 103 are formed from flexiblematerials so that they can be rolled up into a compact form. By way ofexample, the solar collector may be an unglazed plastic flat platecollector. Examples of solar heaters are shown in FIGS. 4-6.

The system 100 may additionally include mounting hardware 105 formounting the solar heater to the roof. Various straps, clips, bracketsmay be used. In one embodiment, the mounting hardware include lagscrews, one or more body straps for securing the absorber to the roof,one or more header straps for securing the headers to the roof, andpossibly some sealant for covering the lag screws.

The piping system 106 includes a first set of pipes 128 that passthrough a pair of roof openings 130A and 130B and that in conjunctionwith a first pump 110 circulates a heat transfer fluid such as waterthrough the collectors 103, drain back tank 116 and a first side of theheat exchanger 108. The first set of pipes 128 may for example passthrough the roof via roof jacks 131A and 131B. One example of a roofflashing is shown in FIG. 7.

The piping system 106 also includes a second set of pipes 129 that inconjunction with a second pump 112 circulates water from a storage tank121 of the hot water heater 120 through the heat exchanger 108 and backto the storage tank 121 of the hot water heater 120. The second set ofpipes may for example correspond to flexible plumbing hoses. In somecases, the second set of pipes 129 may interface the storage tank 121via a tank adapter 118. A tank adapter 118 allows cold and hot water topass through the same opening in the storage tank 121. As should beappreciated, hot water heaters 120 typically only include a singleconnection point for access to the internal volume of its storage tank121 (e.g., drain port). In one embodiment, the tank adapter is formed asa compact part with all of its various conduits at substantially thesame location. In fact, in one implementation, the compact tank adapteris formed as a single integral member. In addition, the tank adapter maybe configured to be about the size of a hand. Examples of tank adaptersare shown in FIGS. 8-12.

In one embodiment, at least the pipes 128 are formed from flexiblematerials so that they can be rolled up into a compact form.Furthermore, by being flexible, the path of the pipes on the roof aswell as through the roof and house may be easily adjusted or laid out.This simply cannot be done with rigid piping such as copper and rigidplastic materials such as CPVC. By way of example, the pipes 128 may beformed from a flexible plastic material.

In one embodiment, the pipes 128 are embodied as PEX (cross linkedpolyethylene). PEX is composed of high density polyethylene which afterundergoing a physical or chemical induced molecular change creates aproduct which is stable in higher temperatures yet remains flexible andchemically resistant to damage. PEX is also suitable for potabledrinking water and is freeze break resistant which means it can expandto accommodate water that has frozen inside the tubing and contract toits original size when it thaws without damage to the tubing. Otherbenefits include faster installation, lower labor costs, and lowermaterial costs. Installation typically requires very few fittings withno torches, solder flux or chemicals required to make the connections.PEX tubing is typically joined together using a fitting system thatincludes a copper crimp ring that is fitted in the ends of the tubes andcrimped in place using a full circle crimp tool. The crimp tool may alsobe included in the kit. Push fittings may also be used to couple tubingtogether or to couple the tubing to other components including pumps,tanks, collectors, and the like. By way of example, ½ inch (copper tubesize) having ⅝ inch outside diameter PEX tubing manufactured from Wattsmay be used. Furthermore, polysulfone push fittings manufactured bySeatech may be used.

Unfortunately, PEX tubing may degrade over time due to sun exposure(UV). Therefore, the PEX tubing that is situated in direct sun mayinclude a coating, paint, tape or outer sheath to protect it from thesun's rays. In one implementation, the kit includes a roll of UVresistant 12 mil tape that can be applied to the portions of the PEXtubing that would otherwise be exposed. Because two roof penetrationsare used, the length of exposed PEX can be kept to a minimum as forexample less than 12 inches. Alternatively, the PEX tubing may becovered with a UV resistant PE thin wall tubing. Alternatively, the PEXtubing may be covered and insulated with UV resistant elastomericinsulation. Alternatively, the PEX tubing may include a layer of UVresistant paint.

Alternatively or additionally, other plastic tubing materials may beused. The pipes may for example be formed from any of those plasticmaterials used to form the solar collector mentioned in FIG. 4 as theytypically require similar characteristics such as the ability towithstand high temperatures and pressures. By way of example, the pipesmay be formed from a family of plastics known as polyolefins. This mayinclude for example polybutylene, polyethylene, polypropylene andpolypropylene random copolymer (PPR). In one specific example,polypropylene tubing may be used instead of PEX tubing.

The amount of piping that is provided in the kit is typically associatedwith what is needed in a conventional home when installing a solarsystem on a roof. The length of tubing needs to cover that amount thatruns along the roof and the amount that runs through the roof andvarious walls until it reaches its required destination proximate thehot water heater (×2—cold and hot). By way of example, the length ofrolled up tubing may be about 100 feet.

The system 100 may additionally include mounting hardware such as tubingsupport clips that support the tubing every 3 ft. and elbows that holdand bend the tubing at 90 degrees. A tubing cutter may also be included.

The drain back tank 116 and associated level 117 are disposed along thefirst set of pipes 128 between the collectors 103 and the heat exchanger108. The drain back tank 116 provides a storage location where fluidinside the collector loop can drain when fluid is not circulating. Inthis system, the collectors 103 only have fluid in them when the firstpump 110 is operating. This means that each night, there will be nofluids in the collector 103 that could possibly freeze or cool down anddelay the start up of the system 100. This also protects the system 100in case of a power failure that prevents the pump 110 from circulatingwater through the collector loop. One example of a drain back tank isshown in FIG. 13.

In the embodiment shown in FIG. 3, the fluids circulated into thecollectors 103 are separated from the heated water of the hot waterheater 120 by the heat exchanger 108. The heat exchanger should beconfigured to prevent contamination of the two loops. The heat exchangeris used to transfer heat from the fluids circulating through thecollectors to the fluid circulating from the hot water heater. Thefluids used in the collector loop can be widely varied. The fluids maybe selected from water, oil, antifreeze, refrigerant, glycol, or thelike. Often times, systems that utilize drain back tanks use distilledwater as the heat transfer fluid circulating through the collector loop.

During operation, the solar controller 114 is configured to activate thefirst and second pumps 110 and 112 to provide circulation though the twoloops. The first pump 1 10 is configured to pump hot water from thesolar heater to the heat exchanger and cold water from the heatexchanger to the solar heater. The second pump 112 is configured to pumpcold water from the hot water heater to the heat exchanger and hot waterfrom the heat exchanger to the hot water heater. In some cases, theactivation is controlled in accordance with temperature readingsassociated with a first sensor located at the hot water heater and asecond sensor located at the collector. For example, the controller mayreceive temperature signals from the sensors and determine when thepumps 110 and 112 should be activated in order to move fluids throughthe system. This timer has easy to use controls and set operation. Italso includes an astronomic feature that automatically adjusts forseasons, geographical locations, sunrise and sunset.

In one embodiment, the heat exchanger 108, pumps 1 10 and 112 areintegrated into a single integrated circulation module 134. This allowsfor easy installation as the associated pipes are simply plugged intothe heat exchanger and the pumps are operatively coupled to the solarcontroller 114 via a wired or wireless connection. In some cases, thesingle integrated circulation module may additionally include the drainback tank and the solar controller for increased integration. Oneexample of a single integrated circulation module is shown in FIG. 14.

It should be appreciated that the kit is not limited by the componentsdescribed, and may include additional components and in some cases fewercomponents depending on the kit. By way of example, the kit may beembodied without a drain back tank, or control module if the kit isdirected towards a passive system. In addition, the kit may includeother components such as fittings for making all the necessary fluidconnections, hardware components for mounting the Drain back tank to awall, as well as hoses, valves, and/or the like.

Add on kits may also be available. Add on kits are kits that supplementthe basic component of the system 100. They may be included together inthe same box or alternatively they may be packaged in separate boxes.This generally depends on their size and weight. By way of example, asecond tank can be added on for additional solar water storage. This isparticularly useful for large households or where large draws of waterare taken every day. In this example, the cold water supply is connectedto the solar storage tank, and the outlet of the solar storage tank isconnected to the inlet of the electric or gas water heater. Additionallyor alternatively, additional solar collectors and associated drain backtanks if needed may be available as add-on kits. Additional union pushfittings may be included in the add-on kit to connect the added solarcollector(s). Additionally or alternatively an anti scalding valve maybe provided through an add-on kit. This type of valve protects usersagainst accidental scalding hot water getting to your faucets.

In one embodiment, the only tools that may be required of an installerare a drill, 1″ hole cutter, socket driver, and a screwdriver for thedrill.

FIG. 4 is a diagram of a solar panel 150, in accordance with oneembodiment of the present invention. The solar panel 150 may for examplecorrespond to the solar collector described in FIG. 3.

As shown, the solar panel 150 includes an absorber 152 and a pair ofheaders 154. The headers 154, which are positioned at opposite ends ofthe absorber 152, tend to be parallel with one another and substantiallyperpendicular to the absorber 152. The bottom header 154 fluidly couplesto the bottom end of the absorber 152 and the top header 154 fluidlycouples to the top end of the absorber 152. Fluids may therefore passbetween the headers 154 and the absorber 152.

The absorber 152 is configured to capture solar heat from the sun and totransfer the solar heat to a fluid inside the absorber 152. During thedaytime, the sun heats up the surface of the absorber 152, and the wallspass this heat to the fluid contained inside the absorber 152. Theabsorber is typically black to maximize absorptivity in order tooptimize amount of energy absorbed from the sun. The bottom header 154A,which provides minimal storage, is configured to receive and temporarilyhold incoming cold water as for example from a city source, well orstorage tank. The top header 154B, which also provides minimal storage,is configured to temporarily hold and help deliver outgoing hot water asfor example to an auxiliary tank or a point of use. In one embodiment,the solar panel operates under low pressure (0-8 psi) and relative lowtemperature (150 F. max).

In accordance with one embodiment, the absorber 152 and headers 154 areformed from plastic materials. In some cases, they are formed from thesame plastic material and in other cases they are formed from differentplastic materials with similar properties. Plastic parts are low costand easy to manufacture. Furthermore, they are lightweight when comparedto traditional materials (e.g., glass and metal pipes). By decreasingthe weight of the system, the system is much easier to assemble andinstall on a roof.

The components including the absorber and headers may for example beformed from a variety of suitable plastics including polyolefin's. Thismay include for example polybutylene, polyethylene, polypropylene andpolypropylene random copolymer (PPR). Each of these has advantages anddisadvantages that should be taken into account when designing thevarious components.

Unfortunately, because of the high heats and pressures associated withcollectors especially those involved in domestic hot water heating, someplastic parts may have a tendency to degrade and/or fail. For example,the plastic parts may creep over time. As such, the components of thesystem such as the absorber, headers and/or storage tanks are formedfrom plastic materials that can withstand high temperatures andpressures, and more particularly from highly creep resistant plasticmaterials.

In one embodiment, the plastic material is selected to withstandpressures in the range of about 40 psi to about 100 psi (e.g., homewater pressure) at temperatures of between about 120 degrees F. to about200 degrees (e.g., operating temperature of the collector). Moreparticularly, the plastic material is selected to withstand pressures ofat least 60 psi, at temperatures of at least about 160 degrees F. Evenmore particularly, the plastic material is preferably selected towithstand pressures of at least 80 psi at temperatures of at least about180 degrees F. The plastic material may also be required to withstandthese parameters for a select amount of time as for example a minimum of10 years. Yet another requirement of the plastic material may be towithstand these parameters for a select dimension of the components asfor example the diameter of the tubes associated with thecollector/absorber (e.g., ¼-⅛ in.).

In one particular embodiment, polypropylene random copolymer (PPR) isused for at least the collector (absorber) since it has been found towork particularly well in the aforementioned system. It can also be usedfor the headers and storage tanks. In another particular embodiment,polybutylene is used for at least the collector (absorber) since it hasalso been found to work well. It can also be used for the headers.

In some embodiments, at least a portion of the various components areformed from the same plastic materials. For example, all the componentsmay be formed from the same plastic material, or a subset of thecomponents may be formed from the same plastic material while theremaining component may be formed from a different material. In anotherembodiment, the various components are all formed from different plasticmaterials. In yet another embodiment, each component may be formed fromdifferent materials. For example, the top header may be formed from afirst material, and the bottom header may be formed from a secondmaterial. As should be appreciated, each part typically has differentdesign considerations that are taken into account when selecting theappropriate plastic material.

In one example, the headers may be formed from polypropylene and thecollector/absorber may be formed from polybutylene or polypropylenerandom copolymer (PPR). Glass filled polypropylene may also be used forthe headers in this example.

It should be noted that the plastic materials mentioned above are notlimited to only the embodiments described herein and may be applied toall types of solar collectors and their various parts. For example, dueto their characteristics, polybutylene and polypropylene randomcopolymer (PPR) are well suited for uses in a wide variety of solarcollectors and solar heater systems. As a result, their uses extend wellbeyond the collector systems described herein. Thus, an independentaspect of the invention is the use of polybutylene and polypropylenerandom copolymer (PPR) in plastic solar collector parts of virtually anytype of solar collector or system.

Moving along, the top header 154B includes an outlet 156 for outputtingheated fluid from the absorber 152 and the bottom header 154A includesan inlet 158 for receiving fluid that is cooler than the heated fluid.Although, the inlet 158 is shown at the bottom left, and the outlet 156is shown at the top right, it should be noted that this is notlimitation and that they may be placed at any point along the top of theabsorber 150 including the opposite sides of the headers 154 or in thecenter of the headers 154.

The outlets and inlets may be widely varied, and may include variouscouplings for fluidly coupling inlet and outlet piping to the collector.In one embodiment, the outlets and inlets are embodied as male stubsthat receive push fittings. Push fittings provide a secure fluidconnection without needing tools. As a result, the collector can beinstalled with simplicity and ease. A user simply has to push thefitting over the male stub to make the connection. The male stubs may beintegrally formed with the headers (molded) or they may be separatecomponents that are attached to the headers (e.g., welded, glued orfused).

Furthermore, the headers 154 may be embodied as a large tube or pipe,and the absorber may be embodied as a panel having one or moreindividual channels or conduits 160. The channels 160 act as passagewaysfor moving the fluid between the pair of headers 154. The channels 160,which may for example take the form of small tubes or pipes, aretypically positioned together side by side (juxtaposed) in a parallelrelationship to form a single absorber panel. The channels 160 may beconnected with one another to form a single integrated piece (e.g.,molded, glued, fused or welded) or they may be separate and distinctparts that are bundled together mechanically (e.g., clips or straps). Inone implementation, individual free-floating tubes are clipped together.In another implementation, the individual tubes are welded togethereither entirely along their length or at spots. In anotherimplementation, the tubes are formed by seam welding two sheetstogether. In yet another implementation, a single sheet is molded with aplurality of tubes.

Moreover, the absorber 152 may be integrally formed with the headers 154(e.g., molded, fused, glued or welded) or it may be a separate piece ofequipment that connects or couples to the headers (e.g., couplings orfittings). In either case, the headers 154 may include a manifold 162,which receives the channels 160 of the absorber 152, and which helpsdistribute the fluid between the absorbers 152 and the headers 154. Inmost cases, the manifold is integrally formed with the headers, andforms a recess within which the ends of the tubes are disposed. In oneexample, the tube ends of the absorber are attached to the manifold viawelding so as to produce a permanent integrated structure consisting ofthe headers and the absorber.

The headers each include one or more openings inside the recess of themanifold that fluidly connect the recess and thus the tubes to a holdingchamber of the headers. The holding chamber represents the area withinwhich the fluid is held until a draw is taken. The opening in the headermay be one continuous opening that extends the length of the header, orit may be segmented openings placed at various points along the lengthof the collector (e.g., holes). By way of example, the tubes of theabsorber may be welded or fused onto the header pipes as described inU.S. Pat. No. 6,038,768, which is herein incorporated by reference.

In one particular arrangement, shown by way of example and not by way oflimitation, the absorber 152 is formed from individual small diameterplastic tubes 160 that are flexible and held together with one or moreclips. In addition, the headers 154 are formed from large diameterplastic pipes that are substantially rigid and have a similar crosssection in both shape and size. The ends of the small diameter plastictubes are welded or fused with the large diameter headers 154 to form asingle unified piece. The plastic material may for example be PPR.

In accordance with one embodiment, the solar panel is configured to workwith both active and passive solar systems. That is, the solar panel isinterchangeable between active and passive systems, i.e., it can beplugged into either system with limited to no adjustments. In activesystems, a pump is used to circulate water from a storage tank throughthe solar panel and back to the storage tank (typically located in thehouse). In passive systems, the heated water is moved via naturalconvection or city water pressure rather than using pumps. Each time ahot water tap is opened, heated water from a storage tank coupled to thesolar panel at its roof location is delivered directly to the point ofuse or indirectly through an auxiliary tank (e.g., hot water heater) viathe pressure of the incoming city water. This feature presents aparadigm shift in the way that solar systems are put together asconventional collectors have been dedicated to either active or passivesystems (e.g., only work with one system).

Not only is the solar panel 150 configured for both passive and activeuse, but it is also configured to be modular so that the overall solarheating system can be configured in a variety of ways. For example, thesolar heating system that uses the solar panel can be configured for avariety of different user loads by adding additional solar panels and/orstorage tanks. In order to achieve this, the solar panel may come instandard shapes and sizes, with standard threads, fittings or couplings,that can easily be plugged into other collectors and/or storage tankswith little effort and possibly no tools. The solar heating system cantherefore be designed to more closely match the actual needs of thedrawing system as well as to better fit within the design constraints ofthe environment in which the solar heating system is used.

As should be appreciated, conventional collectors typically only addressthe needs of one type of user. In contrast, the solar panel describedherein used singularly or with additional collectors and/or storagetanks can be used to address the needs of many users. The solar panel isconfigured in a way to allow the user to customize the collector tostorage ratio, which influences the response time of the system. If theratio of storage to collector is high (more storage, less collector),the user will receive a lot of hot water at the end of the day. If theratio of storage to collector is low (more collector, less storage), theuser will receive small portions of hot water throughout the day. Asshould be appreciated, more collector area generally means that thesystems response is quicker and hotter, but there tends not to be a lotof water stored. Because of the simplicity of the design, thecustomization can be performed during installation, i.e., add one ormore storage tanks if a high storage to collector ratio is needed, add asecond or third collector if a low storage to collector ratio is needed,etc.

In order to accomplish modularity, the solar panel 150 includes standardfittings 161 at the ends of the headers 154. The standard fittings areconfigured across all the components of the solar heating system so thatthe various parts such as multiple collectors and/or storage tanks canbe easily connected to one another.

In one embodiment, as shown in FIGS. 5A and 5B, the ends of each of theheaders 154 includes a male stub 162 that receives a push fitting 164.The male stubs 162 may be formed with the headers 154 or they may beseparate components that are attached to the headers 154 (as shown). Forexample, the male stubs 162 may include a base portion 163 that isdimension to fit within the open end of the header 154, and welded,glued, fused, threaded or otherwise attached to the header 154. The malestubs 162 may additionally include lip covers 165 that fit over the endof the header 154. The lip cover 165 may hide flash. Furthermore, thestub 162 may include a limit mark 166 to indicate when the push fitting164 is properly installed, and chamfered edges 167 to prevent damagingo-rings associated with the push fittings 164.

In order to connect the male stub 162 to another male stub, as forexample a male stub from another collector or possibly a storage tank, aseparate push fitting 164 is used. The male stubs 162 are simply pushedinto opposing ends of the push fitting 164 thereby securing and fluidlycoupling the male stubs together. Alternatively, hoses or pipes can beused between a pair of push fittings if the various components do notexact align at the header ends. By way of example, PEX (Cross-linkedPolyethylene) tubing may be used. Plugs may be used to close off an endof a header that is not desired to be connected to another component.Push fittings may also be used to couple the headers to hoses or tubesas for example cold and hot hoses or tubes (e.g., the cold tube may becoupled to one of the bottom headers via a male stub, and the hot tubemay be coupled to one of the top headers via a male stub). By way ofexample ½ inch or ¾ inch male push fittings may be used.

Although push fittings are shown herein, it should be appreciated thatthis is by way for example and not by way of limitation. As should beappreciated, any suitable coupling arrangement may be used to connectmultiple components together.

The dimensions of the solar panel can be configured in a variety of waysto allow for modularity. For example, they may come in standard sizesand/or in standard increments thereby making connections seamless. Byway of example, the width of the solar panel may formed in 2 ftincrements including 2 ft, 4 ft, 6 ft, 8 ft, 10 ft and 12 ft and so on,and the length may be formed in 2 ft increments including 2 ft, 4 ft, 6ft, 8 ft, 10 ft, 12 ft . . . 20 ft, 22 ft, 24 ft and so on. By usingstandard sizes such as this, various panels can be connected to producethe desired shape and area of the solar collector. For example, two 2×12panels may be combined to cover an area of 48 square feet. In manyapplications it is desirable for the kit to include at least 20 squarefeet or two square meters of collector area, or more preferably morethan 40 square feet or four square meters.

In one implementation, the width of the solar panel is about 2 ft andlength of the solar panel can be selected from 4 ft, 6 ft, 8 ft, 10 ftand 12 ft. In another implementation, the width of the solar panel canbe selected from 4 ft, 6 ft, 8 ft, 10 ft and 12 ft and the length of thesolar panel is about 2 ft. As should be appreciated, the solar panel canbe situated vertically or horizontally depending on the desired needs ofthe system. It should be noted that although these dimensions are given,they are shown by way of example and not by way of limitation.Alternative dimensions may be used although preferably they are standarddimensions for example, metric dimensions may be used. In otherapplications, metric dimensions may be used.

In accordance with one embodiment, the solar panel 150 is rolled up toform a more compact form for packaging. FIG. 6A is a diagram showing thesolar panel 150 in an extended form as for example when its mounted on aroof, and FIG. 6B is a diagram showing the solar panel 150 rolled up andready to be placed inside a box. As shown, in FIG. 6B, the absorber 152is rolled around one of the headers 154 and the rolled bundle is securedwith a strap 168 such as a rope, band, tie, and/or the like. If multiplepanels are to be packaged, they can be stacked together and then rolledaround the headers at one end and the rolled bundle can be securedsimilarly to a single panel without making much impact on the totalpackaged volume.

FIG. 7 is a diagram of a roof jack 170, suitable for use with oneembodiment of the present invention. By way of example, the roof jack170 may correspond to the roof jacks shown in FIG. 3. The roof jack 170is configured to be placed over a roof penetration (e.g., a hole throughthe roof). The roof jack 170 includes a base flashing panel 172 overwhich roof shingles can be placed. The roof jack 170 also includes a hub174 that extends above and seals off an opening in the base flashingpanel 172. During installation of the roof jack 170, the opening/hub 174is disposed over a roof penetration. The hub 174 includes a hole 176through which a pipe or tube can be placed in order to enter the roofpenetration. The diameter of the hole 176 is generally dimensioned toreceive the piping therethrough. Furthermore, the hub 174 is designed toallow the piping enough space to bend through the roof penetration(without kinking). In one implementation, the roof jack 170 is lowprofile and therefore the hub 174 only extends less than 2 inches abovethe base flashing member 172. When the pipe is placed in the hole 176,the interface there between is sealed with a grommet in compression. Thegrommet may be formed from a variety of rubber and other materialsincluding EPDM and nitrile

Although the shape of the hub 174 can be widely varied, in theillustrated embodiment, the hub 174 forms a semi-conical shape. The hole176 is disposed in the bottom end of the conically shaped hub 174. Thehole 176 is therefore situated perpendicular to the surface of the baseflashing member 172 and thus the roof. The roof jack 170 can be formedfrom a variety of materials including plastic and sheet metal. In oneimplementation, the roof jack 170 is formed from galvanized steel sheetmetal similar to other flashings.

It should be noted that the roof jack 170 can be configured toaccommodate more than one pipe. For example, it can be configured withmultiple holes—one for the hot pipe and one for the cold pipe. This typeof roof jack 170 can be used when a single roof penetration is desired.

FIG. 8 is a simplified diagram of a tank adapter 180, in accordance withone embodiment of the present invention. The tank adapter 180 may forexample correspond to the tank adapter shown in FIG. 3. The tank adapter180 is configured to couple to a single connection point 182 whileproviding two different directional flows through the connection point182. The single connection point 182 may for example be the hose bibconnection of a conventional water heater. In most cases, the tankadapter 180 is generally composed of two conduit parts 184 and 186 thatprovide for different flows but still cooperate to work through oneconnection point 182. The conduit parts 184 and 186 can be separateparts that are attached together or they may be integrally formed (e.g.,molded as a single part). Furthermore, the portion of the conduit parts184 and 186 that intersect the single connection point 182 can bepositioned coaxially or they may be juxtaposed while the opposite endsare typically separated so they can be coupled to other components.

As shown, a first conduit part 184 allows a first flow through thesingle connection point 182, and a second conduit part 186 allows asecond flow through the single connection point 182. The flows may forexample be associated with drawing and returning a fluid. In some cases,the conduits parts 184 and 186 are directed to specific directionalflows—one for draw and one for return, while in other cases the conduitscan be directed to either depending on the needs of the system. In somecases, one of the connection ends 187 extends further from theconnection point than the other connection end 188. The ends oppositethe connection point ends may include additional conduits as needed. Byway of example, they may include a T or Y end.

In one embodiment, the tank adapter is formed as a small compact unit.For example, it may have a outer volume of less than about 22.5 cubicinches, and more particularly less than about 18 cubic inches, and evenmore particularly less than 8 cubic inches. It may also be configuredwith no dimension greater than 10 inches, more particular 8 inches, andeven more particularly 6 inches.

FIGS. 9A-9B are various diagrams illustrating a compact tank adapter200, in accordance with one embodiment of the present invention. Thecompact tank adapter 200 includes a central large diameter conduit 202with one open end 204 and two side extending large diameter conduits 206and 208 fluidly coupled to the central large diameter conduit 202 andextending from the side of the central large diameter conduit 202. Thecompact tank adapter 200 also includes a central small diameter conduit210 that is disposed within the large diameter central conduit 202 andthat runs substantially parallel with the axis of the central largediameter conduit 202. Unlike the central large diameter conduit 202, thecentral small diameter conduit 210 has two open ends 212 and 214 thatextend out of the closed and open end 204 of the central large diameterconduit 202. The central small diameter conduit 210 is fluidly separatedfrom the large diameter conduits 202, 206 and 208. The correspondingopen ends 204 and 214 of the central small and large diameter conduits210 and 202 are fluidly connected to the storage tank at a singleconnection point. The physical connection may be made via an externalthread 216 located at the open end 204 of the central large diameterconduit 202 that mates with the hose bib opening in conventional storagetanks. External threads 218, 220 and 222 may also be disposed at theopen ends of the side mounted large diameter conduits 206 and 208 aswell as one end 212 of the central small diameter conduit 210 so thathose and hose bib connections can be made. For example, the hose bib canbe moved to one of the two side mounted large diameter conduits 206, andhoses can be attached to the other side mounted large diameter conduit208 and the central small diameter conduit 210.

In one example, cold water is pulled through the central small diameterconduit 210 via a hose that couples to the inlet of a heat exchanger,and warm water is returned through the side mounted large diameterconduit 208 via a hose that couples to the outlet of the heat exchanger.Of course the flows can be reversed if needed.

In one embodiment, the size of the threads of the small diameter conduit210 is different than the size of the threads of the large diameterconduits 202, 206 and 208 in order to help prevent a potential mismatchof hoses when the system is being connected to the heat exchanger. Theinlets and outlets of the heat exchanger are also configured to followthis same configuration. By way of example, the central small diameterconduit includes a ½″ thread while all other open conduits include ¾″threads.

In one embodiment, the central large diameter conduit has a length thatallows it to reach through the insulation wall of water heater therebymaking installation easier.

In one embodiment, the cross sectional areas through the variousconduits and tubes are configured so as not to restrict flow. In oneexample, the cross sectional area of the central small diameter tube issubstantially similar to the remaining cross section area of the centrallarge diameter tube at its open end. Generally speaking, the sizes ofthe passageways are balanced to provide smooth flows.

In one embodiment, the central small diameter tube is placed against thewall of the central large diameter tube (as shown). Alternatively, thecentral small diameter tube may be spaced away from the wall of thecentral large diameter conduit. For example it may be disposed along theaxis of the central large diameter tube or alternatively it can be offaxis such that it is skewed to one side. If spatially separated, thecentral small diameter tube may be located using fins or it simply maybe supported at the other end of the closed end of the central largediameter conduit.

In accordance with one embodiment, the tank adapter 200 is formed as asingle integral part. By way of example, the tank adapter 200 may beformed from plastic via an injection molding process. In oneimplementation, 40% glass filled polyphenylene sulfide is used. Thismaterial can be used for potable water (NSF61), its rigid enough forthreads, it can withstand high surface temperatures (greater than 160F.), its ductile enough to prevent breakage, and further it is suitablefor injection molding. One example of this material is Ryton. Of course,other materials may also be used. By way of example, PEX, CPVC,Polypropylene and/or similar materials may be used.

FIGS. 10A-10F show various views of a tank adapter, in accordance withone embodiment of the present invention. Dimensions are shown by way ofexample and not by way of limitation. As can be appreciated by thedimensions, the tank adapter is small and very compact.

FIGS. 11A-11C shows various alternate embodiments of the tank adapter.FIGS. 10A and 10B show a tank adapter formed from two parts. In FIG.10A, the tank adapter 240 includes a 4 way conduit member 242 each withthreaded ends, and a tube 244 with a threaded cap 246 disposed at itsperiphery proximate one of its ends. The cap 246 includes an internalthread for connecting to one of the outer threaded ends of the 4 wayconduit 242. The cap 246 is configured to seal the end off except forthe passageway that extends through the tube 244. The tank adapter 240is formed by inserting the tube 244 entirely through one of the twolongitudinally extending and oppositely placed conduits of the 4 wayconduit member 242, and threading the cap 246 onto the closest threadedconduit that is opposite the end where the tube 244 extends out.

In FIG. 11B, the tank adapter 250 is formed by providing a 3 way conduitmember 252 (T shape) each with threaded ends, and inserting a tube 254through the passageway of the central conduit member 253 and through thewall 255 opposite the opening of the central conduit member 253. Thetube 254 may for example be placed within a hole 256 and thereaftersealed, glued, soldered or otherwise fixed to the 3 way conduit member252.

In FIG. 11C, the tank adapter 260 includes an inner tube 262 that isspaced apart from the outer conduit member 264 via one or more fins 266.The tube 262 can be centered on the axis of the outer conduit member 264(as shown) or it may be offset from the axis of the outer conduit member264.

FIG. 12 is a diagram showing a tank adapter 270 coupled to a hot waterheater 272, in accordance with one embodiment of the invention. The tankadapter 270 may for example correspond to any of those previouslydescribed. As shown, the double inlet/outlet of the central conduit ofthe tank adapter is coupled to the hot water tank at the conventionalhose bib connection point 274. The double inlet/outlet of the tankadapter may for example be threaded into the threaded opening of the hotwater heater using a wrench. The hose bib 276 has been removed from thetank 272 and reconnected to one of the side mounted large diameterconduits. Furthermore, a first pump hose 278 is connected to the centralsmall diameter conduit, and a second pump hose 280 is connected to theremaining side mounted conduit. The water inside the tank 272 is drawnthrough the central small diameter conduit and through the first pumphose 278 to the cold inlet of a heat exchanger. The water isreintroduced into the hot water heater 272 through the second pump hose280, the side mounted conduit and finally through the central largediameter conduit.

In one embodiment, the central small diameter conduit includes a diptube 290 that is either integrally formed therewith or that has beencoupled thereto. The dip tube 290 is a long slender tube that extendsinto the hot water heater 272 above the hose bib connection point 274.The dip tube 290 is configured to pipe water from some distance insidethe hot water heater 272 (extends the intake past the centerline ofwater heater and from higher locations within the hot water heater). Thedip tube 290 may for example extend halfway into the storage tank 272.The addition of the dip tube 290 is believed to improve performance ofthe system by allowing water to be pulled from a more central locationthan at locations proximate the bottom of the tank 272 where harmfulparticles may rest. The dip tube 290 may be configured to draw waterfrom 8″ to about 18″ above the tank bottom to prevent sucking in dirt,silt, and other precipitates.

The tube 290 may be formed from a flexible material in order to help inplacing it inside the tank 272. This is in part due to the domed sectioninside conventional water heaters 272. A rigid tube must be forced andsometimes doesn't work at all. The flexible dip tube 290 tends to flexand bend as needed very easily (slide upward against the dome section).In one embodiment, the tube 290 is configured with a density of less 1gram/cc. If density of tube is less than 1 gram/cc then the tube 290tends to rise or float upward once inside the tank 272. The length ofthe tube 290 can therefore be used to position the end of the tube 290in the desired location within the storage tank 272. In one embodiment,the dip tube 290 is formed from polymers and more particularly frompolyolefins. In one implementation, the tube 290 is formed frompolyethylene. In another implementation, the tube is formed from PEXtubing. In another implementation, the tube is formed frompolypropylene.

It is also believed that having a dip tube 290 at higher locationswithin the tank 272 may promote mixing of the water contained inside thetank 272. By drawing heated water, and inserting new warm water, it isbelieved that a stirring effect can be created. As should beappreciated, the incoming hot water tends to migrate to the upperportion of the storage tank, while the colder water already inside thestorage tank tends to migrate to the lower portion of the tank. That is,the hot water flowing out of the tank adapter rises to the top of thestorage tank since its lighter than the water currently in the storagetank and the heavier cold water already in the storage tank falls to thebottom of the storage tank. Without this stirring effect, the hottestwater in the upper region of the storage tank would be drawn out. As aresult, the system may run out of hot water more quickly or only providelukewarm water when draws are taken.

FIG. 13 is a perspective diagram of a drain back tank 300, in accordancewith one embodiment of the present invention. The drain back tank 300 isconfigured to be a holding tank for the collection loop. It also allowsfluid in the collector to drain in order to prevent freezing. Inaccordance with one embodiment, the drain back tank 300 is formed form aplastic materials. For example, it may be formed from any of thoseplastic materials already mentioned. In one particular embodiment, thedrain back tank 300 is formed from polypropylene, which has a higherservice temperature than polyethylene. In one example, the polypropylenetank is blow molded. Because the tank 300 is formed from plastic, anddue to its volume, the tank 30 may include one or more support members302 between front and back walls of the tank 300. The support members302 help prevent the holding tank from collapsing and bowing due to theweight of the fluid contained therein. The support members 302 may beinternally located or they may form a portion of the external enclosure.

In the illustrated embodiment, the drain back tank 300 includes a pairof support cylinders 302 disposed through the tank 300. The supportcylinders 30 are part of the external structure of the front wall thatbends back and structurally connects to the back wall. The cylinders 302may form a hole through the tank or they may form a void with the backwall of the tank. The drain back tank 300 may also include an inlet atthe top wall and an outlet at the bottom wall of the tank. Theinlets/outlets 306 may include standard fittings for receiving thepipes. The drain back tank 300 may further include a vented cap 310,which can serve as a location for adding more fluid into the collectionloop. The drain back tank 300 may also include an external levelindicator 312.

In one embodiment, the drain back tank 300 is wall mountable. As such,it can be designed with support brackets integral with the enclosure(part of molding). The support brackets may for example be configured toreceive the heads of screws or bolts which are fixed to a wall.Alternatively, the back wall of the enclosure in the void formed by thecylinders 302 may include through holes for mounting the drain back tankto the wall with screws or bolts (e.g., lag bolts). The dimensions ofthe tank can be widely varied. In one example, the tank has dimensionsless than 36×12×6 inches, and more particularly about 31×12×5.6 inches.In another example, the drain back tank can be configured to hold about10 gallons.

FIG. 14 is a diagram of a circulation module 320, in accordance with oneembodiment of the present invention. By way of example, the circulationmodule 320 may be used in the system shown in FIG. 3. The circulationmodule 320 integrates various control components into a single unit. Thecirculation module 320 includes a heat exchanger 322, a first pump 324,a second pump 326 and related piping that is disposed inside a compactenclosure 328. If needed, the circulation module 320 may includeelectronic components as well as a power supply that powers both pumpsfrom a single power cable (120 AC).

The heat exchanger 322 includes a set of inlets and outlets for thecollection side and a set of inlets and outlets for storage side. Whenthe fluid on the collection side of the heat exchanger 322 is hotterthan the fluid on the storage side of the heat exchanger 322, the heatis transferred to the fluid inside the storage side of the heatexchanger 322 and this heated fluid is circulated into the storage tank.The inlets and outlets may be ¾ solder connections.

Although the heat exchanger 322 can be widely varied, in the illustratedembodiment, the heat exchanger 322 is a corrugated plate design thatsupports high fluid flow through the unit. This type of design along mayhelp to suspend any particles in the system and minimize the scalingeffect. As should be appreciated, scaling is a natural phenomenon thatexists predominantly in operations involving laminar flows at hightemperatures (e.g., over 140 F.). The corrugated plates may for examplebe stainless steel with copper brazing. The heat exchanger 322 isgenerally configured to be a compact unit that provides a significantamount of heat exchanger surface area to total volume of the heatexchanger 322. Thus, the heat exchanger 322 can be made smaller andlighter which is better for packaging. In one example, the ratio ofsurface area to volume is greater than 50, and more particularly around57.6. By way of example, the heat exchanger may provide about 1.2 squarefeet of surface area with a volume of about 0.21 cubical feet (e.g., 3in.×8 in.×1.5 in.). Furthermore, this can all be accomplished with aweight of about 3 lbs. Alternatively, the heat exchanger 322 may be acoil design. The heat exchanger 322 may be double walled to preventcontamination between the two loops.

The pumps 324 and 326 are connected to the inlets and outlets of theheat exchanger 322 via pipes. The pipes may for example be copper pipes,but may also be plastic pipes to reduce weight and cost. The other sideof the pumps 324 and 326 may be configured to various fittings for easeof installation. On the collection side, the cold outlet pipe of theheat exchanger 322 is typically coupled to a first end of the first pump324, and the cold circulation piping of the system is connected to theother end of the pump 324. In addition, the hot circulation piping ofthe system is connected to the hot inlet pipe. On the storage side, thecold inlet pipe of the heat exchanger 322 is coupled to a first end ofthe second pump 326, and the other end of the pump 326 is coupled to thecold outlet of the storage tank via some piping (e.g., PEX tubing orcopper). Furthermore, the hot outlet pipe of the heat exchanger 322 isconnected to the hot inlet of the storage tank via some piping (e.g.,PEX tubing or copper). The various inlets and outlets of the module 320may include fittings appropriate to the type of piping used. Forexample, on the collection side, the inlet and outlet of the module 320may include push fittings for coupling to PEX tubing. Also by way ofexample, on the storage side, the inlet and outlet of the module 320 mayinclude threads for receiving the ends of conventional flexible plumbingpipe.

By way of example, the pumps may run at about 1/25 hp and range betweena maximum FT head of 6.6 to about 34.8, a maximum GPM between 7 to about8, maximum Watts between about 25 to about 135, a maximum weight betweenabout 6 lbs to about 7.25 lbs.

The enclosure 328 is configured to surround and protect the componentsof the module 320 as well as to provide a clean nice looking aestheticalappearance for the module 320. Although various materials may be used,in the illustrated embodiment, the enclosure 328 is formed from plastic.By way of example, the enclosure 328 may be formed via an injectionmolding operation. The plastic material may be widely varied. In oneexample ABS plastic is used. In another example, 30% fiberglass/mineralreinforced homopolymer polypropylene may be used.

In one embodiment, the enclosure 328 is embodied as a two piece designhaving a first member 330 and a second member 332 that come together toform the overall enclosure 328. This two part design allows forinstallation of the heat exchanger 322 and pumps 324 and 326. It mayinclude locking tabs or snaps 334 for releasably attaching the twohalves together. It may also include various holes 336 through which theinlets and outlets emanating from the heat exchanger 322 and pumps 324and 326 are disposed. By having these external to the housing,installers can easily make the appropriate connections without openingthe enclosure. The enclosure 328 may also include vents 338 to preventpump overheating. Although not shown, the enclosure 328 may furtherinclude a foam base to encapsulate the heat exchanger 322 and help holdthe assembly inside the enclosure 328.

FIG. 15 is a diagram of a packaging arrangement 350 for a solar systemkit, in accordance with one embodiment of the present invention. Thepackaging arrangement 350 may, for example, be used to package thesystem kit shown in FIG. 3. The packaging arrangement 350 is configuredto fit in an outer box 352 that conforms to the size requirementsassociated with the OS2 shipping standard. The weight of the packagingarrangement 350 in addition to the outer box 352 are configured toconform to the weight requirements associated with OS2 shippingstandard. For example, the combined length and girth of the box exceeds108 inches and actual weight of everything box included is less than 70pounds. The volume of the box may also be widely varied, by way ofexample, boxes having volumes of less than about 20-25 cubic feet (e.g.less than approximately 0.7 cubic meters) as for example in the range ofapproximately 13-18 cubic feet have been found to work well. In oneparticular application, a box having dimensions of 22-½″×20-¼″×58-½″ hasbeen used. However, it should be appreciated that the size of the boxmay be widely varied. The important factor is that the box be sized sothat it can be readily shipped at low costs using standard carriers. Inthe illustrated embodiment, the total weigh of box and its contents isless than approximately 70 pounds. Although this is generally preferred,in alternative embodiments heavier boxes may be used. With currentshipping standards, weights of no more than 100 pounds are generallypreferred, with weights less than 90 pounds (OS3) and 70 pounds (OS2)being generally more preferred.

As shown, the packaging arrangement 350 may include one or more sets offlexible tubing 354 that is rolled up into a compact form. Because thepiping is rolled up, the ratio of piping distance to packaged volume issignificantly increased.

The packaging arrangement 350 may also include one or more solar panels356 that are rolled up into a compact form. If multiple panels aresupplied, then the panels 356 can be stacked and rolled up together withlittle impact on total size. Because the panels 356 are rolled up, theratio of collector area to packaged volume is significant increased. Thesolar panels 356 may for example correspond to the solar panel shown inFIGS. 4-6.

The packaging arrangement 350 may also include a circulation module 358that is packaged in a separate “inner” box that is placed within themain or “outer” box. The separate inner box helps support thecirculation module 358 in the outer box. This box may also include anyparts associated with the circulation module 358 as for example acontroller, temperature sensors, wires, pump hoses, etc. The circulationmodule 358 may for example correspond to the circulation module shown inFIG. 14.

The packaging arrangement 350 may also include a drain back tank 360that is packaged in a second separate inner box. The second separateinner box helps support the drain back tank 360 in the outer box. Thisbox may also include any parts associated with the drain back tanks 360as for example inlet and outlet fittings, vent caps, drain tube, andmounting hardware, etc. The drain back tank 360 may for examplecorrespond to the solar panel shown in FIG. 13.

The packaging arrangement 350 may also include various accessories 362that are packaged in one or more additional inner boxes. In oneembodiment, multiple stacked boxes are used. In another embodiment, asingle box is used. In either case, each set of accessories 362 istypically packaged in its own packaging such as plastic bags or boxes.In fact, in order to make assembly easier, the accessories 362 may bepackaged together according to a specific assembly task. The accessories362 can be selected from fittings, valves, tools, hoses, mountinghardware, tape, sealants, sealers, roof jack, and the like. Theaccessories 362 can also be selected form any of the accessories neededfor tubing, solar panels, control module, and drain back tank.

In one example, the circulation module is placed inside its own innerbox, the drain back tank with fittings, caps and drain tube are placedin their own inner box, and the remaining accessories are placed in theaccessory box. The accessories may for example include fittings, tubingcutter, valves, hoses, controller, roof jack, tape, manual, sealer, andthe like.

The packaging arrangement 350 may also include various dividers 362 andfillers 364 to keep the internal boxes from moving or shifting duringshipping. By way of example, the packaging arrangement 350 may includeone or more void fillers or divider pads.

The packaging arrangement 350 may be assembled as follows. The rolled uppiping 354 may be placed at the bottom of the outer box 352. A dividerpanel 362 may be placed over the piping 354 to provide a floor for theremaining components. The circulation module and drain back tank boxes358 and 360 may be placed on the divider panel 362, and the accessorybox 362 can be placed on the circulation module box 358. Furthermore,the rolled up solar panels 356 can be placed in the remaining volume,and a top void filler 366 can be placed over the solar panels 356.Thereafter, the box 352 can be sealed.

In one embodiment, the outer box has a size of about 22-¼″×20″×39-⅞.″The piping as a size of about 20″×20″×5.″ The circulation module box hasa size of about 12-½″×8-¼″×16-¾.″ The drain back tank box has a size ofabout 8″×20″×34-¾. The accessories box has a size of about 14″×8″×18.″The solar panels (which may, for example be 2′ by 12′, have a rolled upsize of about 14″×14″×30.″ Furthermore, the divider may have a size ofabout 22-¼″×20″×1-4,″ and the top void filler may have a size of about14″×12″×4-¾.″

FIG. 16 is a chart showing a parts list for a solar system kit, inaccordance with one embodiment of the present invention. The parts listmay for example correspond to the solar system kit shown in FIG. 3.Furthermore, the parts may be packaged according to the packagingarrangement shown in FIG. 16. As shown, the kit weighs in less than 70pounds and therefore it can be shipped using the OS2 standard.

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. It is therefore intended that thefollowing appended claims be interpreted as including all suchalterations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

1. A solar water heating kit packaged in a single shipping box that hasa weight that is not greater than 100 pounds, the kit comprising: atleast one flexible solar collector panel having a pair of header pipes,the at least one flexible solar collector panel(s) having a cumulativetotal of at least 20 square feet of collector surface area; an interfacemodule that includes a heat exchanger; and a piping system for couplingthe solar panel to the interface module, and for coupling the interfacemodule to a storage tank that is not part of the kit, wherein the pipingsystem includes at least 40 feet of flexible tubing.
 2. A solar waterheating kit as recited in claim 1 wherein the kit further comprisesinstructions for assembling a solar water heating system and the kitcontains all of the necessary components for the solar water heatingsystem.
 3. A solar water heating kit as recited in claim 1 wherein theflexible solar panel is rolled around one of the header pipes within theshipping box.
 4. A solar water heating kit as recited in claim 1 whereinthe single shipping box has a volume that is not greater than 25 cubicfeet and conforms with at most an OS3 shipping standard.
 5. A solarwater heating kit as recited in claim 4 wherein the single shipping boxconforms with an OS2 shipping standard.
 6. A solar water heating kit asrecited in claim 1 wherein the interface module is a single unit thatincludes a first pump suitable for circulating fluid through a firstcirculation loop that includes the solar collector panel and the heatexchanger, and a second pump suitable for circulating water through asecond circulation path that includes the heat exchanger but isindependent from the first circulation loop.
 7. A solar water heatingkit as recited in claim 6 further comprising a control unit suitable forcontrolling operation of a solar water heating system that can be formedfrom the solar water heating kit.
 8. A solar water heating kit asrecited in claim 6 further comprising a tank adapter suitable forcoupling the second circulation path to a domestic hot water tank.
 9. Asolar water heating kit as recited in claim 7 wherein the tank adapteris formed from a plastic material and has an inlet port and an outletport that are adapted to mate with a single domestic hot water tankdrain port.
 10. A solar water heating kit as recited in claim 7 whereinthe tank adapter has a third port in communication with the inlet portand a fourth port in communication with the outlet port and a fifth portthat
 11. A solar water heating kit as recited in claim 1 furthercomprising a drain back tank suitable for holding a sufficient quantityof water to drain the collector panel.
 12. A solar water heating kit asrecited in claim 1 wherein the kit includes at least two solarcollectors that have a combined surface area of at least 40 square feetand the piping system includes at least 70 feet of flexible tubing, thekit further comprising a plurality of push fitting connectors forcoupling the flexible tubing to other components of the solar waterheating system.
 13. A solar water heating kit packaged in a singleshipping box that has a volume that is not greater than 25 cubic feetand a weight that is not greater than 100 pounds, the kit comprising: atleast one flexible solar collector panel, the at least one flexiblesolar collector panel(s) having a cumulative collector surface area ofat least 40 square feet; at least 60 feet of flexible tubing; a tankadapter suitable for coupling the flexible tubing to a water storage orwater heating tank.
 14. A solar water heating kit as recited in claim 14further comprising: a pump; and a control unit for controlling operationof a solar water heating system that can be formed from the solar waterheating kit, including controlling operation of the pump.
 15. A solarwater heating kit as recited in claim 2 wherein the single shipping boxconforms with an OS2 shipping standard.
 16. A tank adapter, comprisingan integrally formed plastic body having at least first, second andthird connection points and first and second fluid conduit passages thatare fluidly separated, wherein the first and second conduit passagesboth open through a first connection point that is adapted to mate witha single tank port, the first conduit passage additionally opens at thesecond connection point, and the second conduit passage additionallyopens at the third connection point.
 17. A tank adapter as recited inclaim 16 wherein the second conduit passage opens substantially at thefirst connection point, the tank adapter further comprising an extensiontube that is fluidly coupled to the first conduit passage and extendsbeyond the first connection point so that when the tank adapter iscoupled to a tank, the inlet of the second conduit passage issubstantially at the first connection point and the outlet of the firstconduit passage may be positioned within the tank at a location that isphysically separated from the inlet of the second conduit passage.
 18. Atank adapter as recited in claim 17 wherein the extension tube extendsat least 10 inches beyond the first connection point so that when thetank adapter is coupled to a tank, the first conduit passage may bepositioned within the tank at a location that is physically separatedfrom the inlet of the second conduit passage by a distance of at least10 inches.
 19. A tank adapter as recited in claim 17 wherein theextension tube is integrally formed with the plastic body.
 20. A tankadapter as recited in claim 17 wherein the extension tube is notintegrally formed with the plastic body.
 21. A tank adapter as recitedin claim 17 wherein the overall outer volume of the compact tank adapteris less than 22.5 in³.
 22. A tank adapter as recited in claim 17 whereinnone of the dimensions of the compact tank adapter are greater than 8inches.
 23. A tank adapter as recited in claim 17 wherein: the tankadapter has four arms that extend along two substantially perpendicularaxes such that the tank adapter substantially has a “t” shape; the firstconduit path extends substantially through first and second arms of thetank adapter along a first axis; the second conduit path extends throughthe first arm and a third arm partially that is perpendicular to thefirst arm; and wherein the tank adapter further comprising a thirdpassage in fluid communication with the second passage, the thirdpassage being arranged to extend through a fourth arm of the tankadapter.